This invention relates generally to the field of telecommunications and more specifically to a method and apparatus for the delivery of multimedia content in a variety of telecommunications networks. In particular it involves the delivery of adapted multimedia content, and further the delivery of optimized multimedia content.
Studies of Deep Packet Inspection (DPI) logs on a number of mobile networks show that video traffic is predominantly due to “Video Browsing” and not “on-deck” video streaming. Video browsing includes access to videos on web sites such as YouTube—YouTube.com which accounts for about 5% (by volume) of all traffic.
The steep rise in video traffic is expected. Mobile internet usage is an increasingly popular market trend. About 15% of 3G users use 3G modems on their notebooks and netbooks to access the internet and video browsing is a part of this usage. The popularity of devices such as the iPhone is also having an impact as about 30% of iPhone users browse videos because of its wide screen feature and easy to use web browser. More devices are coming on the market with similar wide screens and HVGA resolutions and devices with Wide VGA screens are also becoming available (e.g. Samsung H1/Vodafone 360 H1 device with 800 by 480 pixel resolution).
Consumer video devices capable of recording high definition (HD-720 or 1080 height) videos are rapidly spreading in the market today. Not only cameras, but also simple to use devices such as the Cisco/Pure Digital Flip HD cam. These devices provide an increasingly simple way to share videos. The price point of these devices and the simplicity of their use and the upload of videos to the web will have a severe impact on mobile network congestions. Internet video is increasingly HD, and mobile HD access devices are in the market to consume such content.
AT&T reported that its wireless network traffic has quadrupled over the past year. Date: Oct. 13, 2009. http://www.att.com/gen/press-room?pid=4800&cdvn=news&newsarticleid=27226. Adrian Scase, head of the 3GPP, speaking at the Supercomm show in the US indicated that performance numbers “can be misinterpreted”, he warned. “It's always dangerous when you extract one or two headline figures performance figures from a specification,” he told the audience. Data rates per user will vary considerably, depending on a range of factors from the cell size, number of users in that cell, device type and interference conditions.
Wireless traffic is increasing and although peak bitrates are increasing significantly the variability in effective rates means that many networks will become congested and many users will experience varying levels of experience if these factors are not taken into consideration in media delivery.
Multimedia streaming services, such as internet TV (IPTV), video on demand (VoD), and internet radio/music, allow for various forms of multimedia content to be streamed to a diverse range of terminals in different networks. The streaming services are generally based on streaming technologies such as Real Time Streaming Protocol (RTSP), Hyper Text Transfer Protocol (HTTP) progressive download, Session Initiation Protocol (SIP), and variants of these standards (e.g. adapted or modified). We will refer to these protocols or their variations RTSP-like, HTTP-like and SIP-like.
Broadly speaking, three types of content are typically streamed, live, programmed, or on-demand. Programmed and on-demand generally use pre-recorded media content.
With streaming technologies, live or pre-recorded media is sent in a continuous stream to the terminal which processes it and plays it (display video or pictures or play the audio and sounds) as it is received (typically within some relatively small buffering period). To achieve smooth playing and avoid a backlog of data, the media bit rate should be equal to or less than data transfer rate of the networks. Streaming media are usually compressed to bitrates which can meet network bandwidth requirements. As the transmission of the media is from a source (e.g. streaming server or terminal) to terminals, the media bit rate is limited by the bandwidth of the network uplink and/or downlink. As the problems encountered in the uplink and downlink are fundamentally similar, and without a loss of generalization, we will use the downlink case in our illustrations.
The networks supporting multimedia streaming services are packet-switched networks, which include 2.5G, 3G/3.5G packet-switched cellular network, their 4G and 5G evolutions, wired and wireless LAN, broadband internet, etc. These networks have different downlink bandwidths because different access technologies are used. Further, the downlink bandwidth may vary depending on the number of users sharing the bandwidth, or the quality of the downlink channel.
Consider cellular networks as examples. A cellular network is a radio network made up of a number of cells each served by a fixed transmitter, known as base station. Within a cell, a mobile terminal (handset or a PC with a wireless/cellular access card) receives and sends signals over radio waves through a base station. The downlink is the communication link used for the transmission of signals from a base station to the handset.
General Packet Radio Service (GPRS) in a 2.5G GSM cellular network can provide a typical throughput of 115 kbps. Enhanced Data Rates for Global Evolution (EDGE), which is a merely software enhancement over GPRS. 3G networks (e.g. WCDMA and CDMA-2000) offer higher high spectral efficiency and a theoretical maximum data rate of typically 384 kbps per user.
High-Speed Downlink Packet Access (HSDPA) is a 3G/3.5G communication protocol in the High-Speed Packet Access (HSPA) family. It is used in networks based on Universal Mobile Telecommunications System (UMTS) to improve downlink performance. Current HSDPA deployments support down-link data rates of 1.8, 3.6, 7.2 and 14.4 Mbps. Long Term Evolution (LTE) and Advanced LTE are new radio technologies that deliver access speeds that are five to 10 times that of HSPA respectively. Although each generation of networks includes enhancements (for example EDGE is an enhancement of GPRS), it is common to refer to 2.5G or 2.75G networks as 2G networks, as well as to the 3.5G, 3.75G networks as 3G networks.
Mobile online video viewing continues to thrive with the bandwidth expansions from 3G to 3.5G and 4G, and the availability of browsing and video friendly devices, such as netbooks and wide-screen handsets. Mobile video data has substantially increased today to account for about 30% of overall traffic on many mobile networks. Industry projections of video traffic point to a continuous acceleration and warn of looming mobile network congestions.
Although downlink bandwidths vary for different packet-switched networks, one common fact is that the downlink bandwidths are limited. Means have to be found to use this limited resource most effectively.
A challenge that multimedia streaming services bring to networks is that multimedia streaming services are data communication intensive applications where the perceived media quality is directly related to bitrates. On one hand, the network operators or services providers want to improve viewing or listening experience by transmitting high quality media with high bit rate; on the other hand, they need to restrict the media bit-rate to allow sound transmission for a given downlink and allow more users to access the service. This is the case regardless of the type of user terminal, whether it is a handset, netbook, laptop with a wireless/cellular data card, or a laptop/PC connected through the plain old modem, DSL, Cable or Ethernet. Without a loss of generality we will use the user mobile handset to illustrate a typical user terminal.
This multimedia communication challenge cannot be solved by simply increasing the downlink bandwidth by upgrading or replacing the existing network infrastructures. Firstly, the high cost of network expansion prevents network operators from continuously replacing the new network infrastructure. Secondly, upgrading networks usually requires user equipments to be upgraded too, which prevents the upgrades from bringing immediate benefits to the existing customers who are often reluctant to upgrade their user equipments.
Similarly, in the “wireline” world, the network bandwidth is limited by the type of connectivity (optic fiber, copper, fixed wireless). It is not simple for wireline operators to add bandwidth by upgrading their equipment. This is a costly and labor intensive operation.
To minimize the impact on networks and subscriber experience of this growth in video traffic, video traffic optimization strategies will be an unavoidable part of overall traffic optimization strategies of operators
Thus, there is a need in the art for improved methods and systems for adapting multimedia content in various telecommunications networks to optimize media delivery.